38
votes
Why do unfinished basements need GFCI outlets?
Even "dry" concrete contains considerable water, and is a relatively good conductor. So, it's a relatively good path to ground for a person touching it, increasing the odds of a lethal shock.
...
- 202k
35
votes
Is it OK to create a third prong ground from a cold water pipe, for a 2-wire circuit?
When or is it NEC code compliant to upgrade a 2-wire circuit, by adding a third prong equipment ground from a nearby galvanized cold water pipe?
Never!
Article 250.118 of the National Electrical ...
- 19.8k
29
votes
Why does US Code not allow a 15A single receptacle on a 20A circuit?
Let me give some framework around what ThreePhaseEel said.
I can understand wondering that, since UK appliances all have fuses in their plugs, and I bet the fuses are sized to protect the appliance.
...
28
votes
Accepted
Why does US Code not allow a 15A single receptacle on a 20A circuit?
The key lies in the way UL tests 15A and 20A receptacles
Answering this question requires a deep dive into the standard UL tests 15A and 20A receptacle devices to, namely UL 498. In particular, we ...
- 81.8k
26
votes
Accepted
Can I run stripped Romex/NM through conduit?
The wires in NM aren't labeled for use outside the cable jacket, and may not be the correct type for use in conduit to begin with
First off, the wires inside a NM cable are not marked or labeled at ...
- 81.8k
24
votes
Accepted
Can I legally add an outlet with 2 screws when the previous outlet was passthough with 4 screws?
Adding the short wire is called pigtails and it is code compliant so yes you can do this.
Pigtails are a superior way of making connections in my opinion. The pigtails do not add to the wire volume in ...
- 102k
22
votes
Can I legally add an outlet with 2 screws when the previous outlet was passthough with 4 screws?
The most important rule in NEC is 110.3(B), which requires you to follow labeling and instructions... which means read them.
In this case, that only makes things better, particularly the boldface in ...
20
votes
Accepted
Does the NEC allow a sub panel to be powered by a generator and an automatic transfer switch?
Sure, this isn't an issue
What you're proposing isn't a problem at all from a Code standpoint. In fact, it's the normal way automatic transfer is done in facilities that have more complex power needs, ...
- 81.8k
18
votes
What range of heights are allowed for wall receptacles?
The NEC doesn't count a receptacle above 5-1/2' to satisfy the requirement -
210.52(4) Located more than 1.7 m (51⁄2 ft) above the floor
The NEC doesn't have a lower limit for height, in fact 210....
- 25k
17
votes
Is this wiring safe and is it according to code?
There is one safety issue here
It appears that the original installer took the ground wire from the 12/3 cable, looped it around one switch ground screw, then attached it to the other switch ground ...
- 81.8k
16
votes
How should I mount conduit to my wood-laped siding?
Those hangers will stick out and potentially catch on clothing.
I would use saddles.
- 19k
16
votes
How do I properly prepare stranded wire for a screw down connection?
As a Brit who uses far more stranded wire than solid [I don't do first fixes, that's someone else's job], there are two ways to do it 'properly', but this can depend on how much room you have in your ...
- 10.5k
15
votes
Why do unfinished basements need GFCI outlets?
You don't need GFCI receptacles anywhere. Nobody cares how you provision the GFCI protection. You are welcome to have one GFCI device and feed all the receptacles from the protected zone (LOAD) of ...
15
votes
Accepted
Does electrical code allow NEMA 14-60R receptacles in residential settings?
You can have a 14-60R in your house, but it must be on a dedicated branch circuit
There is nothing in the NEC that prohibits you from having a 60A (or larger!) receptacle in your house. (While NEMA-...
- 81.8k
15
votes
Can I use a 125A panel with a breaker and wiring sized for 90A?
I'm going to venture to guess that your inspector is conflating a service with your feeder. A service is the connection from the house to the utility supply. Normally there is no over-current ...
- 27.9k
14
votes
Accepted
Does the NEC require cable to not be twisted?
There are no requirements to not twist the wire, and this is especially difficult to ensure when fishing wire without staples as allowed in “old work” installations.
To fully answer the general ...
- 5,227
14
votes
Best way to cover exposed THHN cables where conduit has been pulled out
The conduit entering the box evidently needed, but someone thought it didn't need, an expansion fitting. They appear to have also skipped glue, as I don't see any remains of glue or broken conduit in ...
- 202k
12
votes
Accepted
OK to bundle wires together in conduit with colored electrical tape?
It's mandatory
When putting identical-appearing circuits in a conduit, you must differentiate them somehow. It's mandatory.
I would not bundle them but mark them individually. Black(blue) and ...
12
votes
Accepted
Can I run my three-way travelers in a 14/2 without a neutral in the cable?
This is not allowed because it violates the rule that in any cable there must be two conductors carrying equal current in opposite directions so the magnetic fields cancel. That T- T Loop top right ...
- 20.9k
12
votes
Accepted
Will this electric panel pass NC inspection?
The clearance requirement is almost definitely going to be an issue. (And not an unusual issue - I will have the same problem if/when I ever upgrade my panel and get it inspected.) The shelves should ...
12
votes
When running a bigger wire to deal with voltage drop on a 240V circuit, do I now need to run a neutral as well?
My question is now that I'm running a 30 amp wire and only using 20 amps, do I need to run a neutral to send the unused 10 amps back the supply?
There is no 'unused 10 A'.
However (and this is ...
- 584
11
votes
Why aren't AFCI breakers required for bathrooms/lavatories?
We're reading tea leaves here to guess at NFPA's intent. National Fire Protection Association (NFPA) writes the "model electrical code" which they offer for anyone in the world to adopt as ...
11
votes
Accepted
Are GFCI outlets allowed on new circuit installations?
The Code doesn't specify location of protection.
NEC 2017
210.8 Ground-Fault Circuit-Interrupter Protection for Personnel.
Ground-fault circuit-interrupter protection for personnel shall be
provided ...
- 16.6k
11
votes
Accepted
How should I mount conduit to my wood-laped siding?
For EMT (anyway) the spacing is pretty clear - I can't recall if it's the same or different for other types, but it might well be the same.
Within 12" of each box. 10 feet maximum spacing (1 ...
- 202k
11
votes
How do I properly prepare stranded wire for a screw down connection?
For screw terminal attachments, it's an acquired skill. You have to be self-demanding and refuse to walk away from a connection that isn't top shelf. If you continue to iterate on the problem, you ...
11
votes
Accepted
110.15 High-Leg Marking
The excerpt is referring to marking inside a 3-phase panel. Unlikely that you'd see that in residential in the US/Canada, but they do exist here and there, especially in mixed-commercial space that ...
- 6,744
11
votes
Accepted
What is the correct way to wire a Relay In Box (or similar relay) that has low-voltage signal wires bundled with 120V wires?
You're on the right track. The same manufacturer (and others) make similar relays where the low and high voltage wires come out opposite sides of the device, with either the high voltage or low ...
- 34.3k
11
votes
How do I wire to NEC code my detached garage?
Subpanel rating >= feeder wire rating >= supply circuit breaker
Tires come in several speed ratings. 85 MPH, 112 MPH and 130 MPH. Subpanels come in 70A, 100A, 125A and 225A. It's only a "...
10
votes
Can I run #14 armored cable behind baseboards?
NEC 300.4(D) covers the type of installation indicated in the question, and it applies to both AC and MC armored cable. So you'll need to use a steel guard at least 1/16" thick to protect the cable. ...
- 25k
10
votes
Accepted
Why are 120 V general receptacle circuits limited to 20 A?
Why 20A? Receptacle design constraints, most likely
The reason why general receptacle circuits top out at 20A is because the notion of a duplex receptacle doesn't work for larger plug sizes (just can'...
- 81.8k
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